diff options
Diffstat (limited to 'usr.bin/head/head.c')
| -rw-r--r-- | usr.bin/head/head.c | 215 |
1 files changed, 215 insertions, 0 deletions
diff --git a/usr.bin/head/head.c b/usr.bin/head/head.c new file mode 100644 index 000000000000..62796ae144a1 --- /dev/null +++ b/usr.bin/head/head.c @@ -0,0 +1,215 @@ +/* + * SPDX-License-Identifier: BSD-3-Clause + * + * Copyright (c) 1980, 1987, 1992, 1993 + * The Regents of the University of California. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. Neither the name of the University nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#include <sys/capsicum.h> +#include <sys/types.h> + +#include <capsicum_helpers.h> +#include <ctype.h> +#include <err.h> +#include <errno.h> +#include <getopt.h> +#include <inttypes.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> + +#include <libutil.h> + +#include <libcasper.h> +#include <casper/cap_fileargs.h> + +/* + * head - give the first few lines of a stream or of each of a set of files + * + * Bill Joy UCB August 24, 1977 + */ + +static void head(FILE *, intmax_t); +static void head_bytes(FILE *, off_t); +static void obsolete(char *[]); +static void usage(void) __dead2; + +static const struct option long_opts[] = +{ + {"bytes", required_argument, NULL, 'c'}, + {"lines", required_argument, NULL, 'n'}, + {"quiet", no_argument, NULL, 'q'}, + {"silent", no_argument, NULL, 'q'}, + {"verbose", no_argument, NULL, 'v'}, + {NULL, no_argument, NULL, 0} +}; + +int +main(int argc, char *argv[]) +{ + FILE *fp; + off_t bytecnt; + intmax_t linecnt; + int ch, first, eval; + fileargs_t *fa; + cap_rights_t rights; + int qflag = 0; + int vflag = 0; + + linecnt = -1; + eval = 0; + bytecnt = -1; + + obsolete(argv); + while ((ch = getopt_long(argc, argv, "+n:c:qv", long_opts, NULL)) != -1) { + switch(ch) { + case 'c': + if (expand_number(optarg, &bytecnt) || bytecnt <= 0) + errx(1, "illegal byte count -- %s", optarg); + break; + case 'n': + if (expand_number(optarg, &linecnt) || linecnt <= 0) + errx(1, "illegal line count -- %s", optarg); + break; + case 'q': + qflag = 1; + vflag = 0; + break; + case 'v': + qflag = 0; + vflag = 1; + break; + case '?': + default: + usage(); + /* NOTREACHED */ + } + } + argc -= optind; + argv += optind; + + fa = fileargs_init(argc, argv, O_RDONLY, 0, + cap_rights_init(&rights, CAP_READ, CAP_FSTAT, CAP_FCNTL), FA_OPEN); + if (fa == NULL) + err(1, "unable to init casper"); + + caph_cache_catpages(); + if (caph_limit_stdio() < 0 || caph_enter_casper() < 0) + err(1, "unable to enter capability mode"); + + if (linecnt != -1 && bytecnt != -1) + errx(1, "can't combine line and byte counts"); + if (linecnt == -1) + linecnt = 10; + if (*argv != NULL) { + for (first = 1; *argv != NULL; ++argv) { + if ((fp = fileargs_fopen(fa, *argv, "r")) == NULL) { + warn("%s", *argv); + eval = 1; + continue; + } + if (vflag || (qflag == 0 && argc > 1)) { + (void)printf("%s==> %s <==\n", + first ? "" : "\n", *argv); + first = 0; + } + if (bytecnt == -1) + head(fp, linecnt); + else + head_bytes(fp, bytecnt); + (void)fclose(fp); + } + } else if (bytecnt == -1) + head(stdin, linecnt); + else + head_bytes(stdin, bytecnt); + + fileargs_free(fa); + exit(eval); +} + +static void +head(FILE *fp, intmax_t cnt) +{ + char *cp = NULL; + size_t error, bufsize = 0; + ssize_t readlen; + + while (cnt != 0 && (readlen = getline(&cp, &bufsize, fp)) >= 0) { + error = fwrite(cp, sizeof(char), readlen, stdout); + if ((ssize_t)error != readlen) + err(1, "stdout"); + cnt--; + } +} + +static void +head_bytes(FILE *fp, off_t cnt) +{ + char buf[4096]; + size_t readlen; + + while (cnt) { + if ((uintmax_t)cnt < sizeof(buf)) + readlen = cnt; + else + readlen = sizeof(buf); + readlen = fread(buf, sizeof(char), readlen, fp); + if (readlen == 0) + break; + if (fwrite(buf, sizeof(char), readlen, stdout) != readlen) + err(1, "stdout"); + cnt -= readlen; + } +} + +static void +obsolete(char *argv[]) +{ + char *ap; + + while ((ap = *++argv)) { + /* Return if "--" or not "-[0-9]*". */ + if (ap[0] != '-' || ap[1] == '-' || !isdigit(ap[1])) + return; + if ((ap = malloc(strlen(*argv) + 2)) == NULL) + err(1, NULL); + ap[0] = '-'; + ap[1] = 'n'; + (void)strcpy(ap + 2, *argv + 1); + *argv = ap; + } +} + +static void +usage(void) +{ + + (void)fprintf(stderr, "usage: head [-n lines | -c bytes] [file ...]\n"); + exit(1); +} |